This invention generally relates to the reduction or organic contaminants and the biological oxygen demand of an aqueous waste stream from a process for producing phenol from cumene.
There are several processes for the production of phenol, in addition to the recovery of phenol from cracked hydrocarbons, but by far the most commercial process involves the cleavage of cumene hydroperoxide into phenol and acetone. Just as in most chemical reactions, by-products are formed contaminating the products and recoverable reactants which must be removed from the system. Even removing the contaminants from the reaction system results in problems, particularly to the environment, since they are disposed of only with significant difficulty. The byproducts and contaminants which are removable as organic materials are typically burned as fuel to provide energy, but aqueous streams containing only small amounts of such contaminants cannot be economically incinerated and cannot be discharged to the environment without considerable treatment.
Previously, the organic contaminants of the aqueous waste streams have been removed by a number of different systems. For instance, in the production of phenol from the catalytic cracking of hydrocarbons, U.S. Pat. No. 3,304,253 describes the use of a light catalytic cycle oil, having a limited content of aromatic materials, as an extractant to remove phenol from a waste water stream. While satisfactory recovery of phenol can be accomplished through the use of many extraneous solvents added to the system or through the use of a product stream in the process, it has not heretofore been recognized that a highly aromatic fraction of an organic waste stream indigenous with the phenol process itself would be useful in lowering the biological oxygen demand of the aqueous waste from the process.
Accordingly, it is an object of this invention to use a fraction of an organic waste stream indigenous to the phenol process to reduce the biological oxygen demand and phenol content of aqueous waste from the process. It is a further object of this invention to use such indigenous waste stream in this manner and still take advantage of the fuel values of such waste stream in ultimate disposal.